public class t815 {

    public static void main(String[] args) {
        //815. 公交路线 困难 优化建图 bfs 不会 看不懂
        int routes[][] ={{1,2,7},{3,6,7}};
        int source = 1;
        int target = 6;
        System.out.println(numBusesToDestination(routes, source, target));
    }
    public static int numBusesToDestination(int[][] routes, int source, int target) {



        return 0;
    }
}
